Certain cosmetic, pharmaceutical, household, industrial, and food related products are formulated with multiple phases which need to be kept separate until ready for use. The ability of the package to keep the multiple phases separate until ready for use, as well as provide the consumer with an easy to use device has heretofore been a major obstacle.
Previous attempts to package such multiple phase products included packaging each phase of the product in separate containers which need to be opened separately and mixed within a third container before use by the consumer. The problem with the use of this style package is that a container for each phase, as well as a mixing container, has to be packaged in a single shipping container for sale to the consumer. This increased number of components required for packaging the product for sale increases the cost of the product as well as the cost to ship the product to its intended destination.
Other systems have been proposed which utilize a separate pump for each phase of the product, wherein each of these pumps is bound by a common actuator. Aside from the complexity of the pump structure and the increased costs associated with using this type of complicated dispensing system, there still remain significant drawbacks to this system. First, as is common with multiple phase products, each phase of the product typically does not have the same physical properties as the other phases. When these phases are placed in a multiple pump system the different physical characteristics associated with each phase can cause inaccuracies in the priming of each individual pump, the dose expelled by those pumps, and the resultant uneven use-up of each phase of the product thereby typically leaving one phase remaining in its respective container while the other phase is spent. These problems become especially prevalent when the multiple phase product requires exacting metered doses of each phase to be mixed together in order to obtain the optimum properties of the product.
French Patent 2,721,907, describes a dosing mechanism for dispensing two products at the same time. This structure comprises a box having two distinct containers, and a double piston extending across the two containers. The double piston has a control mechanism attached to it. The control consists of a screw threaded shaft attached to the top of the container, and a nut which runs on the shaft. The nut is attached to the double piston so that rotation of the shaft advances the nut and moves the pistons within their respective containers. The drawback to this dispenser is that the overall height of the container has to be at least double the height of the individual containers in order to dispense substantially all of the product contained therein. This is because each container must have an uninterrupted wall in order to keep the two products contained therein separate. With this uninterrupted wall, the double piston must have an upside-down U shaped member which connects the piston within each container to the shaft. This U shaped member must be at least as long as each container. If the U shaped member were not at least as long as each container, then either the entire contents of the container would not be dispensed, or each container wall would have to be provided with a slot within which the piston could travel so that the piston could reach the bottom of the container. Either of these configurations is not practical because one is forced either to design a package which is relatively lengthy or one which does not dispense all of the product within each container.
French Patent 2,651,485, discloses a container/dispenser for two different products of a similar consistency. The container consists of a housing with two separate chambers for the two products, and a mechanism for expelling them through two separate outlets at the top which is operated by an actuator with access from the outside of the container. The mechanism for expelling the products is in the form of pistons inside the two chambers, operated by a telescoping screw mechanism and a knurled wheel the knurled wheel engages with cogs on the ends of the piston screws to drive the pistons within the two chambers. Similar to French Patent 2,721,907, this dispenser has to have an increased height so that the telescoping screw member can be fully contained within the dispenser.
Additionally, many if not most of the multiple phase dispensing systems, such as those described above, require the consumer to mix each phase of the product together after dispensing. Typically, in the case of topically applied pharmaceutical or cosmetic products, the consumer must dispense each phase of the product onto the intended area of the body. Then, the consumer must mix the multiple phases together in order for the product to perform its intended function. The problem with having a consumer mix a multiple phase product directly on the skin is that, before the phases are mixed together, the consumer may have an adverse reaction to any one of the phases in its unmixed form.